Forbid mouse pointer to go to second monitor windows 10 while in extend mode?

Question

I am using windows 10 extend mode for my second monitor. I am using full screen browser mode on my primary monitor to play a game and have dragged a video to my second monitor.

After I have dragged my video (which is now playing) to my second monitor, I want to forbid my mouse pointer to be able to cross over from my primary monitor on to my second monitor which is the default behaviour with this extend mode.

Is there any way I can assign prefferably a hotkey to disable this behaviour and lock my mouse pointer to my primary monitor?